I’ve only been in the hospital myself a few times, luckily, but I’ve visited others, and chatted with people too. It seems that a high percentage of the time, any jello distributed in the hospital is green. Any idea why?? The only theories we’ve come up with are:
Any thoughts?
Psssssstt! Over here! Shhhh, just between you and me.
Two words: Soylent Green.
'Nuff sed.
Finally! A thread I can answer!
My Grandma (the best school lunch lady Peters Township Pennsylvania ever had!) once asked the Kraft foods rep why professional food-service packs of lime Jell-O were available in four, eight and ten gallon packages, while orange, lemon and cherry Jell-O only came in four gallon packets. He said that was because hospitals used so much.
Hospitals believe the cherry unpopular among the injured (a bloody red gelatinus dessert after my skin graft? Why not!) and that the orange and lemon were to tangy for the queasy or weak of constitution. So lime won by default.
I was given a different reason for the lack of red jello.
In case of vomiting, they want to know that red means blood, not jello. You can’t get red popsicles, either.
Why don’t they have green cherry?
The relative likelihood of allergies to red food coloring might have something to it, too. And green is so soothing!
DUH! Cuz green cherries aren’t ripe! 
Ditto for what comes out the other end–the red food dye in Jello (and Kool-aid) comes through basically unchanged, as anyone who has ever changed a diaper for a toddler who drinks a lot of Kool-aid can attest.’
What about white grape?
Are you sure hospital jello is invariably green? We seem to have a lot of orange and yellow stuff available here, too.